Advisory details:
ubuntu_osv / UBUNTU-CVE-2025-39905
| Advisory ID | ubuntu_osv/UBUNTU-CVE-2025-39905 |
| Aliases |
CVE-2025-39905
|
| Summary | In the Linux kernel, the following vulnerability has been resolved: net: phylink: add lock for serializing concurrent pl->phydev writes with resolver Currently phylink_resolve() protects itself against concurrent phylink_bringup_phy() or phylink_disconnect_phy() calls which modify pl->phydev by relying on pl->state_mutex. The problem is that in phylink_resolve(), pl->state_mutex is in a lock inversion state with pl->phydev->lock. So pl->phydev->lock needs to be acquired prior to pl->state_mutex. But that requires dereferencing pl->phydev in the first place, and without pl->state_mutex, that is racy. Hence the reason for the extra lock. Currently it is redundant, but it will serve a functional purpose once mutex_lock(&phy->lock) will be moved outside of the mutex_lock(&pl->state_mutex) section. Another alternative considered would have been to let phylink_resolve() acquire the rtnl_mutex, which is also held when phylink_bringup_phy() and phylink_disconnect_phy() are called. But since phylink_disconnect_phy() runs under rtnl_lock(), it would deadlock with phylink_resolve() when calling flush_work(&pl->resolve). Additionally, it would have been undesirable because it would have unnecessarily blocked many other call paths as well in the entire kernel, so the smaller-scoped lock was preferred. |
| Status | Published |
| Exploitability | 0.5 |
| Weighted Severity | 6.3 |
| Risk | 3.1 |
| Affected and Fixed Packages | Package Details |
| Introduced and Fixed Package Commit Patches | Package Commit Patches Details |
| There are no known CWE. |
| System | Score | Found at |
|---|---|---|
| cvssv3.1 | 7.0 | https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-39905.json |
| ubuntu-priority | low | https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-39905.json |
| Reference id | Reference type | URL |
|---|---|---|
| https://git.kernel.org/linus/0ba5b2f2c381dbec9ed9e4ab3ae5d3e667de0dc3 | ||
| https://ubuntu.com/security/CVE-2025-39905 | ||
| https://www.cve.org/CVERecord?id=CVE-2025-39905 | ||
| 0ba5b2f2c381dbec9ed9e4ab3ae5d3e667de0dc3 | Other | https://git.kernel.org/stable/c/0ba5b2f2c381dbec9ed9e4ab3ae5d3e667de0dc3 |
| 56fe63b05ec84ae6674269d78397cec43a7a295a | Other | https://git.kernel.org/stable/c/56fe63b05ec84ae6674269d78397cec43a7a295a |
No EPSS data available for this advisory.
| Patch URL | |
|---|---|
| There are no known patches. | |
| Attack Vector (AV) | Attack Complexity (AC) | Privileges Required (PR) | User Interaction (UI) | Scope (S) | Confidentiality Impact (C) | Integrity Impact (I) | Availability Impact (A) |
|---|---|---|---|---|---|---|---|
network adjacent_network local physical |
low high |
none low high |
none required |
unchanged changed |
high low none |
high low none |
high low none |
There are no SSVC decisions available.